Wireless Telegraphy and Telephony
Forfatter: Alfred P. Morgan
År: 1917
Forlag: The Norman W. Henley Publishing Company
Sted: New York
Udgave: Third Edition, Fully Illustrated
Sider: 33
UDK: 621.396.1 Mor
A practical Treatise on Wireless Telegraphy and Telephony, giving Complete and Detailed Explanations of the Theory and Practice of Modern Radio Apparatus and its Present Day Applications, together with a chapter on the possibilities of its Future Development
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WIRELESS TELEGRAPHY
19
The flat-top aerials are gradually coming into very ex-
tended use. They are used to the exclusion of all others
on shipboard. They need not be so high as a vertical type
aerial in order to be as efficient. Flat-top aerials consist
of a vertical portion and a nearly horizontal portion. The
Fig. 16.—A diagram showing pyramid aerial.
horizontal portion is practically useless, as far as its work
in radiating waves is concerned, it being used for the pur-
pose of increasing the capacity of the aerial. An increase
in capacity in an aerial means that more energy can be
stored and radiated. Flat-top aerials have the objection,
however, of possessing a directive action; that is, they
receive, or radiate waves, better in one direction than in
the other. A flat-top aerial always receives or transmits
better in the direction that the ends point than in a direc-
tion at right angles to the wires.
The accompanying diagram is an illustration to show the
effects of the directive action of a flat-top aerial. The black